Copying Windows 7 to a new HDD

So I'm building a new computer and I want to install Windows 7 Ultimate on my new HDD. My friend installed 7 on my old HDD so I don't have a official disk or anything. I know you can boot up windows using a DVD or flash drive. I have a big enough flash drive to handle the installation. What I want to know is if it's possible to copy the 7 OS to my flash drive and load it on the new HDD without having the original boot disk. I've read some info on the subject in other forums and it seems like there's a difference of opinion on how to go about doing this. I'm pretty sure he made my flash drive bootable at one point so once that happens I shouldn't have to do that again right?

So you are asking us for help you make an illegal copy of Windows? Not cool!

Not only are illegal copies of software major sources and major targets of malware, often the compromised machine are then used against honest people. Seeking support for stealing software and/or supporting software thieves is against the Terms of Use you agreed to when you joined this site.

What you need to do is go buy a legal license or if budget does not permit, download and install one of the many free and capable version of Linux.

Topic closed.